Valve for pumps



Feb. 24, 1942., R.P. MxLLER 2,274,084

VALVE FOR PUMPS Filed May 13, 1940 Patented Feb. 24, 1942 UNITED STATE s PATE-NT 'OFFICE This invention relates to automatic pumping f of fluid by fluid pressure; the presentinvention being a continuation in pantof my copending application Ser. No.l 224,887, filed August 15, 1938. The fluid which is to be pumped isrherein refer-red to as production fluid; and the fluid under tend through usual well casing tothe lproduction f' n `zone of the well, with displacement fluid supplied via ,the annular space between the tubing and the surrounding casing, or the flow tubing may surround an inner conduit through which' displacement fluid is supplied.

The invention is applicable to that type of pump in which a foot valve controls admission of production uid to the flow tubing, and ahead Valve controls admission of displacement fluid for elevating thepreviously 'admitted produc tion fluid. Pumping is automatic, the head and foot valves being dependently actuated and alternately opened and closed responsive to pressure differential. At `the start of the filling period,

pressure in the flow tubing is relieved by disg5 charge of anV elevated slug of production fluid so that formation pressure exceeds pressure in the tubing string and thus creates pressure differential for opening the foot valve and closing the head valve. Production fluid then enters and Is rises lin theV flow tubing until pressure in the tubing string, or pressure in the tubing string plus pressure of displacement' fluid opposing opening of the foot valve, exceeds formation with' this pressure differential then automatically decreasing until there is pressure differential in the opposite direction, thereby terminating the filling period and inaugurating ,the discharge period; and such automatic variation in pressure differential is dependent upon variable factors at each installation.

For example, at each installation the relation between these variable factors must include: (1) admission of displacement fluid at pressure and in quantity sufficient to elevate that volume of production fluid which at the end of the preceding lling period has been trapped above the closed foot valve, and (2)'V such' pressure opposing formation pressure against the foot valve, that the resulting pressure differential will open the foot valve and close the head valve to inaugurate the filling period, withthe direction of pressure vdifferential then automatically reversed for closing the foot valve and opening the head valve to inaugurate the discharge period when the volume of production uid which has entered the tubing string is such that the displacement fluid which Ais then admitted to the tubing string will elevate placement fluid exerted against the head valve and opposing ,openingo'f :the foot valve.

Itis a furtherobjectof the invention to prou vide ahead valve ofv sturdy construction and not pressure and thus creates pressure differential in the opposite direction for closingYthe foot valve 'and opening the head valve. This inaugurates the discharge period during which' displacement fluidvforms a fluid'piston forelevating and expelling the production which has been 'trapped I in the now tubing. As the production fluid is elevated and expelled,fthe displacement fluid expands and thereby relieves pressure in the tubing string until said pressureis again exceeded by formation pressure for opening the foot valve and closing the -head valve torestartl the filling period.

Cyclic operation is thus dependent upon pressubject to clogging by sand or the like.

It is astill further object of the invention to proportion the head valve for any desired pressure of displacement fluid opposing opening of the foot valve, and at the same time maintain desired sturdy construction of the head valve.

It yis astill further object of the invention to provide for ready 'interchange of parts for varying :the pressure o f displacement fluid exerted against .thehead valve and opposing opening of the footvalve. f Further objects of `the invention will be readily understood from the following description of the. accompanying drawing, in which:

Fig. 1` is a vertical section through a pump, showingA the head' valve partly in elevation and partly'in axial section.

Figs. `2 and 3 are transverse sections on the *lines 2-2 and 3-'3 respectively of Fig. 1.

sure differential inauguratng the filling period, 5 5

By way'of example, the invention is illustrated anqdescrbed in connection with the pumping of petroleum wells, the pump being installed in flow tubing A which in the present embodiment of the invention is surrounded by well casing A so that the annular space D between the tubing and the casing forms a supply conduit for the gas under pressure which constitutes the displacement fluid. The displacement fluid may be supplied to the space D from an upper gas zone of the well or from the earths surface; and by means of a packer E the annular space D is sh'ut off from the production fluid which enters the well casing from :the production zone of the well. This production fluid enters the lower end of the flow tubing A and rises therein, seeking its static or working level.

Valve mechanism comprising a dep'endently actuated head and foot valve is mounted in the flow tubing. The foot valve B controls admission of production fluid to Ithat portionY of the flow tubing which' is above itsvalve seat I, and the Vhead valve C controls admission of displacement fluid lfrom the annular` space D to that portion ofithe ow tubing which is above the foot valve-VB;

Thevalvemechanism B-C is adapted for mounting in the flow tubing A at any desired .distance below the packer E, whereby the pump may; be operated at a level appreciablybelow the packer or may be operated-at .a level adjacent the packer. Means for supplying displacement fluid from the annular space D to the head valve C includes a screen F at the peripheral wall of the now tubing above the packer E, communicating witha depending conduit G. The lower end of the conduit G communicates with the bore of a guide 2 which is mounted in the lower end of a section of the flow tubing. The valve mechanlsml B--C is suspended from the-bore of the guid'e'2, in a section 4 of the flow .tubing which depends from and is threaded to the section 3 as shownat 5.

Displacement fluid is thus admitted from the annular space D, via the screen F and the conduit G to thebore of the guide 2, and thence via the depending head valve C to the flow tubing A above the foot valve B.

The lhead valve C comprises a cylinder I suspendedfrom and communicating at its upper end Vwith the bore ofY the guide 2, with a valve sleeve I I projecting upwardly from a. cage I2 and adapted for snug'l sliding reciprocation onv the cylinder Ill; When the reciprocating sleeve II 1s at terminal downstroke it uncovers lateral ports I3 in the wall of they cylinder I0 so as to admit displacementiiuid to the flow tubing above the foot valve, and when the sleeve I I is at terminal upstroke it'overlies: and closes the ports I3-and thus shuts off admission of displacement uld to the iiow tubing.

To prevent thelateral discharge of. displace-- Vment -iluid via the, open ports I3.caus1ng-undue female thread extended as shown ati5a for reception of ythe lower portion of the annulus I5` so that it'seats on a shoulder 5b atthe lower end of this recess, and with the end of the male thread adapted to engage'an external annular shoulder |50, which is formed medially of the length of the annulus I5. The upper portion of the wear-resisting annulus, which is of reduced diameter, telescopes within the bore of the male thread. The joint 5 is preferably positioned so as to mount the annulus I5 with the ports I3 in alinement with the annulus medially of its length.

When the head valve C is closed, pressure of displacement fluid supplied via the conduit G is exerted against the valve and tends to open the valve; and for this purpose a predetermined area of the valve is subject to this pressure. As an instance, a pin 20 projects upwardly from the cage I2 for snug sliding reception in the lower end of the bore of the cylinder I0. The pressure exerted against the pin 20 is dependent upon the pressure of the displacement fluid supplied via the conduit' G and the cross-sectional area of the pin; `and in practice pins of different cross-sectional area may be interchangeably employed in cylinders I0 adapted for interchangeable suspension from the guide `2 and having bores which at their upper ends are approximately the same diameter ,as the boreV ofA the-guide 2 but which at their lower ends, below the ports I3, vary in diameter for snug sliding reception of pins 20 of diierent cross-sectional area.

Cylinders I0 may be interchangeably employed by suspending the desired cylinder from the guide 2 by `a detachable threaded connection 2|; and pins 20 may be interchangeably employed by mounting a pin of desired cross-sectional area on its cage I2 by means of a transverse retaining pin 22 which extendsthrough the'base of the cage and the base of the pin.

The foot Valve B is adapted for dependent actuation with the head valve C, so that when the sleeve Il opensv theI ports I3 the foot valve is closed, and .when` the sleeve I I closes the ports I3 thefoot valve is. open. For thispurpose, a valve stem 25 depends from the cage I2, and the foot valve B comprises a Valve head 26 suspended from the stem 25 and cooperating with the seat I to open or close the foot valve.

In operation, formation pressure tends to open the footvalve B and thereby close the dependently Iactuated head valve C; and this pressure is opposed by pressureV in the ow tubing exerted against the upper face of the foot valve and by pressure of displacement fluid supplied via the conduit G and exerted against the pin 29. By selecting a pin 2U of desired cross-sectional area, and a cylinder I0 which below its ports I3 is adapted for'snug slidingI reception of the selected pin, these opposing pressures are such that when pressure in the flow tubing is relieved by elevating and expellinga slug of production fluid, pressure differential opens the foot valve and closes the dependently actuated head valve. Production fluid is thus admitted via the open foot valve and rises in .the flow tubing, seeking its static or working level.

When pressure of the column of production fluid admitted to the ow tubing, plus pressure of displacement fluid against the pin 20, exceeds formation pressure the foot valve closes, thereby opening the dependently actuated head valve. Displacement fluid is then admitted to the ilow tubing via the open ports I3, at pressure and in quantity suihcient to elevate that volume of production fluid which is now trapped in the iiow tubing above the closed `foot valve. The displacement uid thus elevates the production fluid as a slug, and dischargesl the same at the top of the Well, thereby relieving pressure in the flow tube.

By relieving pressure in the ow tubing, formationwpressureagain exceeds pressure in the flow tubing plus p ressure'of displacement iiuidl against the pin 20, thereby reopening thefoot valve and closing the head valve for repeating the `cycle of operation.` v l "v Automatic cyclic operationis thus' dependent upon proper pressure of displacement liuid` opposing opening of the foot valve; and a head valve C constructed as above described* provides a sturdy and reliable construction whereby any desiredratio of'pressure area of the head valve to pressure area of the foot valve may be readily provided. v

This desired pressure ratio is obtained without balancing pressure of displacement iiuid against opposite faces of the head valve, thereby eliminating restricted passages which would be subject to clogging by sand.

Ihe improved construction also eliminates pockets in which sand might collect and prevent desired stroke of the reciprocating valve mechanism B-C, the bore of the sleeve Il between the cage l2 and the lower end of the cylinder l0 being open via lateral ports 30 which preferably form knife-edges 3lv at the bore of the sleeve. Flow of production fluid via the ports 30 thus washes away sand, with no pockets or surfaces on which the sand may accumulate, thereby preventing lodging of sand in the lower end of the sleeve Il or on the cage I2.

Pressure of displacement iiuid is exerted against the pin 20, which is adapted for snug sliding reception in the lower end of the bore of the cylinder Ill; but the foot valve B is suspended not from the pin 20 but from the'valve stem 25. The stem 25 may thus be of adequate cross-sectional area to insure a sturdy construction while the pin 20 may be appreciably reduced in crosssectional area without liability of breaking the pin or weakening the head valve structure. Furthermore, both the stationary cylinder I and the movable parts II-Z may be hardened to a degree which will prevent sand galling the relative movable surfaces Ill-ll or Ill- 20, without the resulting relatively brittle construction being l liable to break as would be the case if the pin instead of the'stem 25 supported the foot valve B.

To prevent sand entering between the sleeve l l and the cylinder I0, or between the pin 20 and the snugly cooperating lower end of the bore of the cylinder I Il, the upper end of the sleeve Il is preferably beveled for knife-edge sliding enand the lower end of the cylinder ID preferably forms an annular pocket, tapering for knife-edge sliding engagement with the pin 20 as shown at 36.

The invention has been described as adapted for interchange of pins 20 (of different pressure area) for regulating the pressure differential so as to close the foot valve and 4open the dependently operated head valve at the end of a desired lling period. The invention is also applicable to a construction such as shown in my aforementioned copending application Ser. No. 224,887, filed August 15, 1938, wherein pressure differential may be regulated by interchanging pins 20 and also by regulating the pressure (in the ilow tubing) which is exerted against the upper face of the foot valve B and which coc operates with the pressure area of the pin 20 for establishing the desired pressure differential.

For example, as ,shown in my aforementioned copending application a valve in the flow tubing (at the earths surface) may be opened during thedischarge period andthen closed fordesired time interval duringtheiilli'ng period, thereby increasing 'the pressure (in the ilow tubing) which `cooperates with the pressure area of the pin 2l)n for establishing the desired pressure differential. A pin 20 of relatively small pressure' aream'ay thusbe employed, since the increased pressure in the flow tubing contributes materie ally to establishing the desired' pressure diierential; and a head valve constructed as herein described permits a pin 20 vof relatively small area being employed, without liability of breaking the pin` and without liability of clogging the head valve. i

l. In valve mechanism for an automatic fluid pressure pump, flow tubing, a cylinder adapted for mounting in the ilow tubing and having a lateral discharge port, means for supplying displacement fluid to one end of the cylinder, a cage adapted for reciprocation at the other end of the cylinder, a sleeve on the cage adapted for snug sliding reception on the cylinder for opening or closing the lateral discharge port, the sleeve having lateral ports between the cage and the proximate end of the cylinder, said ports having knife-edges at the bore of the sleeve, a pin projecting from the cage and adapted for snug sliding reception in the bore of the cylinder, a valve stem projecting from the opposite face of the cage, a valve seat adapted for mounting in the bore of the flow tubing, and a valve head on the valve stem cooperating with the valve seat for controlling oW of production fluid via the bore of the flow tubing.

2. In a valve mechanism for an automatic uid pressure pump, ilow tubing, a cylinder adapted for mounting in the flow tubing and having a lateral discharge port, means for supplying disvgagernent with the cylinder l0 as shown at 35,

placement uid to one end of the cylinder, a cage adapted for reciprocation at the other end of the cylinder, a sleeve on the cage adapted for snug sliding reception on the cylinder for opening or closing the lateral discharge port, the bore of the sleeve being open to the exterior thereof between the cage and the proximate end of the cylinder, a pin projecting from the cage and adapted for snug sliding reception in the bore of the cylinder, a valve stem projecting from the opposite face of the cage, a valve seat adapted for mounting in the bore of the flow tubing, and a valve head on the valve sterny cooperating with the valve seat for controlling ow of production iluid via the bore of the flow tubing.

3. In a valve mechanism for an automatic fluid pressure pump, iiow tubing, a cylinder adapted for mounting in the now tubing and having a lateral discharge port, means for supplying displacement fluid to one end of the cylinder, a cage adapted for reciprocation at the other end of the cylinder, a sleeve on the cage adapted for snug sliding reception on the cylinder for opening or closing the lateral discharge port,` a pin projecting from the cage and adapted for snug sliding reception in the bore of the cylinder, a valve stem projecting from the opposite face of the cage, a valve seat adapted for mounting in the bore of the ilow tubing, and a valve head on the valve stem cooperating with the valve seat for controlling flow of production lluid via the bore of the flow tubing.

4. In a valve mechanism for an automatic 4fluid pressure pump, iiow tubing, a cylinder adapted for mounting in the flow tubing and having a lateral discharge port, means for supplying displacement fluid to one end of V.tlle ,cylin'e der, a sleeve adapted for snug sliding reception on the cylinder for opening or closing the' lateral discharge port, a. pin xed relative to the sleeve and adapted for snug sliding reception in the bore of the cylinder, a. valve stem projecting'from the sleeve, a valve seat adapted for mounting in the bore of the ow tubing, and a valve head on the valve stem cooperating with the valve seat for controllingr flow of production fluid via'the bore of the flow tubing.

5. In avalve mechanism for an automatic liu-id pressure pump, ow tubing, a cylinder adapted for mounting in the flow tubing and having a lateral discharge port and a. restricted bore at 15 one end of the cylinder :beyond the discharge port, `means for supplying displacement uid to the opposite end of the cylinder, a sleeve adapted forsnug sliding reception on the cylinderv for opening or closing the lateral discharge port, a pinA fixed relative to the sleeve and adapted for snug sliding reception in the restricted bore of the cylinder, a Valve stem projecting from the sleeve, a valve seat adapted for mounting in the bore of the ow tubing, and a valve head on the val-ve stem cooperating with the valve seat for controlling flow of production uid via. the bore of the ow tubing.

ROBERT P. MILLER. 

